Perhaps the reach is too long for you, but the other thing can be the cable tension. Granted others can shift without a whole lot of problem, however I've noticed with the guys that they physically push the shifter sometimes where we generally don't. I have used Campy drivetrains since the early 90's and haven't had any issues. One other thing you might try is a teflon coated cable... they are smoother and makes the shifting even easier with less effort. The cables are about $7-$8 and well worth the expense!

Have fun with yur new bike!